Gerard Butler plays a conflicted cop in new crime thriller Den Of Thieves. Laura Harding talks about his career as an action man and whether he would ever return to romantic comedies

IT IS so cold that Gerard Butler's bicep is turning blue. He isn't complaining but the icy air is starting to affect his breathing. It might be something to do with the short-sleeved T-shirt he's wearing while everyone around him is bundled up in parkas, furry hats, scarves and gloves.

The gunfight he is in the middle of filming is meant to take place in sunny Los Angeles, but instead he is freezing on the outskirts of Atlanta, Georgia, where it is hammering with rain and threatening to snow.

"I'm from Scotland so my Scottish blood is helping me," he grimaces. It's not clear who this is convincing. "I got here early before the movie started filming and we had an ice storm and the city shut down and I was like 'I am so f***ed, I'm going to be in a T-shirt every day'."

We are on the set of his new crime thriller Den Of Thieves, in which the Paisley-born star plays a hard-as-nails, heavily tattooed career detective and general alpha dog, known as Big Nick. Thermal underwear and woolly hats wouldn't really fit with the tough guy persona and he's pretty deep into character.

"I started dressing like him, I started walking around like him. I remember I was out at dinner one night with Christian (Gudegast, the director) and I thought I was eating sushi. "Whenever I would do something he would be like, 'The way you put your hand over that glass, that's Big Nick. The way you're eating is Big Nick.' And then he says, 'That's raw chicken that you're eating.' I thought it was fish! But I was just voracious; Nick has that animal-like tendency, like a T-Rex, so while I'm talking and eating and I'm just thinking 'fish', it turns out I had eaten about a pound of raw chicken."

This is a startling revelation but 48-year-old Butler laughs and brushes it off. "I actually wasn't sick, I was surprised," he laughs.

It's a good thing too. A severe dose of food poisoning might really mess up his mojo.

"It was tough to get in this head space. I was super nervous about this movie because it's a very intense character for me to climb into. I don't think you fully get rid of it until the end of the movie. Ambien [the medication used to help insomnia] helps me a lot, but you also do get used to it and you learn to sleep. You switch off, you read, you watch a movie. I like to meditate."

Butler may be best known for action films Olympus Has Fallen and London Has Fallen, as well as fantasy epic 300, but he says thriller Den Of Thieves is more realistic.

"If you compare it to 300, it's a little more real. It really tries to climb into that vibe of cop life and gang life and criminal life. In Olympus and London, we always delve a little more into the ridiculous and that is part of the fun of it. If you stand back and look at it you go, 'Seriously? Is this happening?' But if you go scene by scene, you can buy that it was going on."

The new flick is inspired by some of Butler's favourite cops and robbers films, including Heat and The Town.

"The grittiness and the world they are in reminds me of this movie. And Gene Hackman in The French Connection, that's Big Nick. He's just off. He goes too far, he can't really help himself but he gets the job done."

It's another hard man role for Butler, who first made a name for himself in romantic comedies such as PS I Love You, Dear Frankie and The Ugly Truth, but Butler says he is looking for variety.

"The last movie I did was called A Family Man, about a father whose kid gets leukaemia. The next movie I'm doing is a psychological thriller. This is not an action movie, I don't think it's only action. I am trying to really break it up and do what I think are more interesting roles and interesting scripts but I have deliberately steered away from romantic comedies for a bit. Who is to say I won't go back there? They are fun but you kind of feel you lose your edge a bit. I like keeping some edge."

So what are the chances he will make another romcom? "It's not unlikely, you never know. It just depends on each script. When 300 came along, I had said, 'I am never doing a sword and sandals movie again,' and then 300 came along and I thought, 'I've got to do that'.

He felt the same amount of enthusiasm for Den Of Thieves, in which Big Nick and his crew attempt to take down a crime gang, which includes Curtis "50 Cent" Jackson and Orange Is The New Black's Pablo Schreiber, as they plot to rob the Los Angeles Federal Reserve, the bank for banks. Butler even paid his own visit to the Fed in Los Angeles and was bowled over by what he saw.

"There was one room that had at least a trillion dollars in there. It was interesting to go through there and see all the safeguards they have and, even though they know we are there making a movie, they can never once let us out of their sight. We had to have a guard behind us to make sure that none of us were looking at the wrong things, but I'm a bad boy, I've always got to look at the wrong thing.

"It was just incredible to see that amount of money and the processes for everything, to count the money, to check the money, to look for impurities, imperfections, the amount of money that is destroyed every day."

  • Den Of Thieves is in cinemas now